


Mages In The Surfice

by Isbrandir_Blake



Category: Fate/stay night & Related Fandoms, Undertale (Video Game)
Genre: Blood Magic, Blood and Violence, Chaos, Crossover, F/M, Fifth Holy Grail War, Possession, Timeline Shenanigans, Yandere Chara (Undertale)
Language: English
Status: In-Progress
Published: 2021-01-07
Updated: 2021-02-08
Packaged: 2021-03-18 03:41:09
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death, Underage
Chapters: 4
Words: 1,715
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28611489
Author URL: https://archiveofourown.org/users/Isbrandir_Blake/pseuds/Isbrandir_Blake
Summary: The phantasmal being stared at her intently." Servant, Avenger ...I ask you...Do you wanna have a bad time? " The Servant said, as his left eye flared to life.Chara could not stop herself blushing, giddy.
Relationships: Chara & Sans (Undertale), Chara/Sans (Undertale), Emiya Shirou/Matou Sakura, Iskandar | Rider & Waver Velvet
Comments: 9
Kudos: 16





	1. 8th Servant

**Author's Note:**

> I have very little clue a of where I am going with this

The circle e was perfect. She never gave much thought about drawing with blood, but she is now sure that -after this is over- she will give it a try, since the Scarlet looks beautiful in all this arcane shapes.

Her phone beeped 1 minute to midnight. 

" Let' s do this !" She said, extending her hand, catalyst in her closed fist.

**_Silver and iron to the origin._ **

**_Let the monolith the archduke of contracts to the cornerstone._ **

**_The ancestor is my great master Schweinorg._ **

**_The alighted wind becomes a wall. The gates in the four directions close, coming from the crown, the three-forked road that leads to the kingdom_ **

**_circulate._ **

**_Fill_ **

**_Fill_ **

**_Fill_ **

**_Fill_ **

**_Fill_ **

**_Repeat every five times._ **

**_Simply, shatter once filled._ **

**_The start I announce._ **

**_Your self is under me, my doom is in your soul._ **

**_In accordance with the approach of the Holy Grail, if you abide by this feeling, this reason, then answer._ **

**_Here is my oath. I am the one who becomes all the justice of the world of the forgotten, I am the one who brings out all the evil of the world of the living._ **

**_You, seven heavens clad in three words of power, arrive from the ring of deterrence, O keeper of the balance！_ **

The circle shined red, mana lightning encompassing the room, a thick raze of blue Energy shined.

Her smile did not falter, even as she had to close her eyes to shield herself from the great light of summoning.

Opening her eyes she was greeted with a small being with a gigantic aura to put demigods to shame.

The phantasmal being stared at her intently.

" Servant, **Avenger** ...

I ask you...

Do you wanna have a bad time? " the Servant said as his right eye flared to life.

Chara could not help herself blushing, giddy.

**Notes for the Chapter:**

> I was planning on keeping it more obscure, but a friend recomended me to make it more clear:
> 
> This fic takes place durinduring 5th grail war in early 2000s - which I am making it to be a few decades after the undertale end.


	2. Informational

**Summary for the Chapter:**

> Just a servant sheet

Name: Sans The Skeleton, Sans Aleister Gaster

Servant Class: **Avenger**

Alternate Classes: Archer, Caster, Berserker

Source: 

_**The Opening of Ebots Gates, The Storie of How Monsters Returned to the Surface**_.

Country of Origin: Underground ( U.K.)

Alignment: Neutral Good.

** STAT SHEET **

Strength: D

Endurance: E

Agility: B+

Mana: A 

Luck: D

NP: A+ ~ **EX**

** CLASS SKILLS **

Self-Replenishment (Mana)  : B +

** PERSONAL SKILLS **

The Vision Beyond Time: A+

The Kind Hearted Fool : B+

Karma Retribution: A++

The Ultimate Judge: C+

LV and Brotherhood: D ~ A

Science Prodigy: B

Child a Greater Ghost : EX

** NOBLE PHANTASMS **

**Gaster Blaster -**

The Dragon Skulls of My Late Father

B~A++

Anti-Unit and Anti-Army

1 ~ 300 m range

**My Turn -**

Punishment For The Fallen

A~EX

Anti-Unit

30 m

**Notes for the Chapter:**

> Just to clear things out. Sans NP and skills star are variable because his power depends a lot of the who he is fighting and for how long he has to fight them.


	3. Partnership

"How long this will this take?" The Skeleton asked, impatient and cranky.

" Probally twice what it supppsed to If you keep moving like that. " Chara's melodic new voice answerd, more amused and affectionate than annoiyed, at her servant's behavior.

With a oh-so-jolly demeanur Chara painted dark corintian runes in Sans skull and ribs.

"This will allow my own body enhancment magic to flow through your form, making you more durable and stronger at melee range combat." She had told him, right after asking him to strip.

_I should have tried my luck at killing her when she summoned me_... Sans thought, regretting his post-life choices

~ A few hours earlier~

I ask you...

Do you wanna have a bad time? " The Servant said, as his left eye flared to life.

Chara could not stop herself blushing, giddy.

I less than a moment several floating Dragon skulls appeared through the cavern.

" Ahm, Ahm, Ahm, Comedian." The kid- more like a teenager now that Sans took a better look- said, with a voice very different from what he remembered, but with a tone he recognized well, waving what looked like a detonator ...

_Shit!_

" I have taken precautions for, If you try to hurt this sexy little body I acquired for myself, a ton of explosives will detonate in very populated school...and in your nephew's home."

Sans Gasped, shocked. Shock quickly turned to anger. With a weight even greater that he had in life, Sans expanded his murder aura. " You keep Calibri out of this or else-"

" Or else what, darling? If you kill me, places you do not even know the location of, will turn to ashes pretty fast. If you try to torture me for the information, I got my command seals and the detonator in the left hand. And, just so you know, I ain't no pushover in this body either." She smiled wickedly, gesturing to herself, as many circuit like patterns shined a sickly determined red.

_Fuck... I seriously have no option here, do I?_

The Dragon skulls more well know as Gaster Blasters disappeared, as Sans eyes returned to their original shape.

" What exactly do you want, brat?" He asked, trying to sound as acid as possible.

Her smile widened, eyes shining with magic, satisfaction and... And something else Sans did not want to think about at the moment.

" I want us to work together. The Throne of Heroes must have already filled you in about the war, and about what is to gain here."

" The grail?" He scoffed. " I knew you were crazy but did not take you for an idiot.

Even If we won, the grail is one evil genie- no one that won got what they wanted out of it.

It's a took a gambit."

She giggled - actually fucking giggled like a normal girl, instead of her old crazed laughter- at him, and for the first time he noticed that the freak was wearing clothes that much resembled those he knew from his life ( a green sweater with a yellow stripe and brown shorts, but this time the sweater left much of her shoulders and collarbone exposed and the shorts were very small) _What the fuck?_

"Is a gambit I am willing to take. What else I have to do in this boring little world, anyway? To possess more weak people with uninteresting lives for the rest of eternity?

No Sans, I want to live, I want the world, I want power and I want never to feel bored anymore..."

Her eyes were deep crinson, more intense and honest than he had seen that entire night, and she met his gazed while uttered: " **And I want to do get it with you!** "

...

_Oh, fuck my life! She is determined about it ain't she?_

The skeleton covered his face with his hands in a defeated gesture.

_Well... If it is unavoidable..._

" I will work with you." 

Her eyes widened at that smile fading in a expression of actual surprised.

"But, only If we do this my way. No craziness"

His response was the widest smile of that entire night. 

~~~

In a few minutes the 2 of them started to discuss the war.

_I will regret this really soon, ain't I?_


	4. School Girl ( but not really)

**Notes for the Chapter:**

> I do not why, but I imagined Chara with a Mordred pony-tale.

" Taa-Daah ! How do I look ?" The psycho asked, opening her arms as If expecting a hug or something creepy like that.

Sans looked her up and down.

She was wearing a sort of uniform. Light brown vest over a white dress shirt, skirt came to her mid-thigh, black stockings, simple shoes and he had tied her wild burnett hair in a simple ponytail.

_~~It looks good.~~ _He refused himself to acknowledge

" You look like a Mental Asylum escapee, trying to pass herself for a high-schooler." He answered.

She pouted cutely, at him. " O come on, you know I look great. Why got to be such tsundere."

" To make my freak of a get that I am not here to be budy-budy with her psychotic ass." He put as much bite in his voice as possible.

" Sans-"

"It's Avenger now, brat. Your fault, by the way." The skeleton touched his ( Papyrus) red scarf.

It was really freaky that - even though he was sure his last timeline before true death was a pacifist run in which frisk got everyone out of the underground- he still had his brothers scarf like in his last genocide run.

According to the freak. a few decades passed since he died. Frisk was alive and well living in England, Pap was enjoying his old age with his family, including Calibri, that had made paps a grand-pap. _Hehe, that kid sure was a present . I can still remember when paps called me all exited the baby-bones had given his first step._

He supposed the grail cares more about the point in which you were at the peak of your power and fame, rather than anything else... And his magic was practically 4 times stronger than normal from the determination to make the human reset in his last genocide-run... Avenging everyone... Really was one the great definers of who Sans was.

... He still blamed his master anyway. Well at least like this he will have access to his "true special attack" If he needs to.

"Why are you dressed like that anyway? I know this is Japan but cosplay is a bit of a otakussaration." _Humor, keep the humor to distract yourself from wanting to kill this brat._

" Well , I have you informed that I already localized 2 of the master's we will have to deal with, and both of them are in the same place -"

" Ah pervy school-girl café?" He said, not even sure If it was a thing but happy to see the annoyed expression on the brat's face.

" No ! A actual high school. Which I had already matriculated myself into and will be attending tomorrow." She finished, slightly smug.

"Wait, wait wait. A High-school ?!? Our Murder-game adversaries are in high-school ?!? W.T.F ?!? Is Japan really like in anime and all that is magic and action happens with teens? 'Cause that would be a fucked up reality."

She only lifted an inquisitive eye brown to him. " You seem very savvy of anime culture ... Why is that Sansy?" She affirmed, cheekiness tempering her voice.

He only deadpanned : " I was friends with Alphys, what do you think?"

Chara only shrugged. "Well, anyway, you will go with me in spirit form there tomorrow. Do not worry we will not attack anyone, yet I just wanna check out the competition." she turned her back to him in favor of checking herself in the broken mirror in the wall.

Letting the freak alone to enjoy her own image, he dematerialized.

_Here we go I guess._

**Author's Note:**

> Love feedback  
> Please say whatever is on your minds.


End file.
